In case of treating the device used in the field of semiconductor and liquid crystal, there is frequently utilized plasma energy of a halogen based corrosive gas having a high corrosiveness. For example, in a plasma etching treatment (processing) device as one of the semiconductor processing devices, plasma is generated in a chlorine-based or fluorine-based gas atmosphere having a strong corrosiveness or in a mixed gas atmosphere of these gas and an inert gas, and the semiconductor element is subjected to an etching by utilizing a strong reactivity of ions or electrons excited.
In this processing technique, at least a part of the wall of the reactor or the member or members disposed in the interior thereof (susceptor, antistatic chuck, electrode and the like) are easily subjected to an erosion action by the plasma energy, and hence it is important to use materials having an excellent resistance to plasma erosion. As to such a requirement, there have hitherto been used a metal (inclusive of alloys) having a good resistance to corrosion, and inorganic materials such as quartz, alumina and the like. For example, JP-A-H10-4083 discloses a technique wherein the above material is applied onto the surface of the above member inside the reactor by PVD process or CVD process, or a dense film made from an oxide of a Group IIIa element in the Periodic Table is formed thereon, or Y2O3 single crystal is applied thereon. Also, JP-A-2001-164354 or JP-A-2003-264169 discloses a technique wherein Y2O3 as an oxide of an element belonging to Group IIIa in the Periodic Table is applied on the surface of the member through a spraying process to improve the resistance to plasma erosion.
However, the technique disclosed in JP-A-H10-4083 of applying the metallic oxide of the Group IIIa element in the Periodic Table or the like indicates a relatively good resistance to plasma erosion, but it is a situation in which this technique is not a sufficient countermeasure in the field of recent semiconductor processing technique requiring a higher precision and an environmental cleanness in a severer atmosphere of the corrosive gas.
Also, the member covered with the Y2O3 spray coating as disclosed in JP-A-2001-164354 and JP-A-2003-264169 serves to improve the resistance to plasma erosion, but is required to be further improved because the processing of the recent semiconductor members is under severer conditions that fluorine based gas having a strong corrosiveness and hydrocarbon based gas are alternately and repeatedly used as a processing atmosphere in addition to the plasma etching action of a further higher output.
Particularly, when the F-containing gas and the CH-containing gas are alternately and repeated used, the formation of a fluoride having a high steam pressure is caused by a strong corrosion reaction inherent to the halogen gas in the F-containing gas atmosphere, while in the CH-containing gas atmosphere, the decomposition of the fluorine compound produced in the F-containing gas is promoted or a part of the film component is changed into a carbide to enhance more reaction into a fluoride. Under the plasma environment these reactions are promoted to generate a very severe corrosion environment. Particularly, when the etching is carried out at a high plasma output, the potential difference between the plasma and the inner wall of the plasma treating vessel (chamber) becomes large, and hence the Y2O3 spray coating adhered to the inner wall face is corroded. As a result, the particles of the corrosion product produced under such an environment are fallen off and adhered onto the surface of the integrated circuit of the semiconductor product, which causes the damage of the device.